As a vibrator module in which a piezoelectric vibrator and an IC are used in combination, for example, an oscillation module that oscillates a piezoelectric vibrator at a resonance point to output a clock, a time module, a voltage-controlled oscillator (VCO), a TCXO module in which an EEPROM or the like is mounted and which corrects frequency-temperature characteristics specific to a vibrator, and so forth are commercially available. As another vibrator module, an angular velocity sensor is available, in which, in order to detects a change in vibration state caused by an angular velocity of rotation of a piezoelectric vibrator, a driving circuit that drives the piezoelectric vibrator and a detection circuit for detecting a signal corresponding to a Coriolis force are used in combination. Additionally, an acceleration sensor is available, which detects a change in oscillation frequency in a case in which a vibrating reed of a piezoelectric vibrator receives a stress caused by acceleration. Furthermore, a gas sensor is available, in which a material that absorbs moisture or gas is applied to a surface of a piezoelectric vibrator, and which detects a change in oscillation frequency caused by the absorption concentration of moisture or gas.
As such a vibrator module in which a piezoelectric vibrator and an IC are used in combination, as shown in FIG. 18, a vibrator module in which a vibrator and an IC are embedded in a package is provided. A vibrator module 1 includes a package 2, and an IC 3 is accommodated in the package 2. The IC 3 is bonded to bumps formed on the package 2 by ultrasonic thermal compression bonding or the like. A crystal strip 4 serving as a vibrator is supported by steps of the package 2, and bonded to a crystal-receiving terminal using a conductive adhesive or the like. An opening of the package 2 is covered with a cover 5. The vibrator module 1 is mounted on a circuit board or the like using mounting terminals 6 that are formed on the bottom surface of the package 2.
The size of the vibrator module 1 can be reduced to some content. However, because the IC 3, the crystal strip 4, the cover 5, and so forth need to be bonded to the package 2, the bounding cost becomes high. Additionally, because the package structure becomes complicated, that is not preferable to cost reduction and size reduction.
For this reason, as shown in FIG. 19, a vibrator module 8 has been invented, in which the crystal strip 4 is accommodated in the package 2, in which the IC 3 is disposed above the crystal strip 4, in which the package 2 is air-tightly sealed, and in which a resin 7 is applied onto the IC 3. Because, in the vibrator module 8, the IC 3 serves as a cover, the size of the vibrator module 8 can be more reduced (see Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-72641
However, even in a case of the vibrator module shown in FIG. 19, a problem that bonding cost for bonding the crystal strip serving as a vibrator to the package is increased has not been solved. Additionally, because of the configuration in which the crystal strip and the IC are bounded to the package, there is also a problem that the cost of the package is relatively increased.
In the related art, manufacturing cost of vibrator modules depended on the size of vibrators. In other words, the number of pieces of vibrators that were obtained from one wafer determined the cost of the vibrators. The size of packages was determined in correspondence with the size of vibrators. However, recently, designs capable of reducing the cost of vibrators have been advanced, resulting in a decrease in the size of vibrators. In such a case, a factor in determining the size of vibrator modules has depended on the size of IC chips more than that of vibrators.
Particularly, because an MEMS technology or the like has been developed, it has been possible to manufacture vibrators less than or equal to 1 mm per side. As a result, the tendency has been more increased.
Furthermore, as the size of vibrators is reduced and the packaging density of ICs is increased, the size of vibrator modules is more reduced. In such a case, in the cost of vibrator modules, the cost of precision packages tends to be relatively increased, which is different from a case of large size products manufactured when vibrators and ICs were expensive. Moreover, a problem with a space in which each vibrator is bonded to a package using an adhesive has to be also dealt with in order to reduce the size of vibrators.